Double hook ultrasonic surgical blade

ABSTRACT

An ultrasonic surgical device including an elongate waveguide having a longitudinal axis an a distal end, and a blade extending away from the distal end of the waveguide, the blade including a curved portion that includes first and second opposed faces extending lengthwise along at least a portion of the length of the blade. Each of the first and second faces has a width that extends perpendicular to the longitudinal axis of the waveguide and a length that extends orthogonal to the width. A pair of hook portions are located on opposite sides of the blade. A method of fabricating an ultrasonic surgical device is also provided.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent ApplicationNo. 62/203,694, filed on Aug. 11, 2015, entitled “Double Hook UltrasonicSurgical Blade.” The entire disclosure of the foregoing provisionalpatent application is incorporated by reference herein.

BACKGROUND

Ultrasonically driven surgical blades have been used for quite some timein the cutting, coagulation and/or dissection of tissue during variousmedical procedures. Compared to conventional static scalpels, forexample, ultrasonically driven blades typically require less force forcutting tissue, and can also provide coagulation of blood vessels(particularly when the device includes a clamp member associated withthe blade).

Ultrasonic surgical blades are usually provided at the end of anelongate waveguide, which in turn is operatively coupled to anultrasonic transducer. The transducer, often provided as part of, orhoused within, a handpiece, is adapted to convert electrical energy(typically supplied by an external generator) into vibrational motion,typically longitudinal vibrations, at an ultrasonic frequency. In manyinstances, the transducer includes a “Langevin stack” of piezoelectricdisks for this purpose. The standing wave produced by the transducer istransmitted from the transducer to the waveguide, and propagates thelength of the waveguide to the blade located at the distal end of thewaveguide. As a result, the blade vibrates at an ultrasonic frequency.

When the ultrasonically vibrating blade is urged against tissue, such asby manipulation of a handpiece and/or by clamping tissue between theblade and a clamp member, the mechanical vibratory energy of the bladeis transmitted to the tissue, not only cutting the tissue but alsogenerating frictional heat and causing cavitation, coaptation andcoagulation of the tissue.

In some instances, the blade is straight and, when used with alongitudinally vibrating transducer, vibrates solely in the longitudinaldirection (parallel to the longitudinal axis of the waveguide). However,it is often desirable to provide ultrasonically driven blades that arecurved in one or more directions. Curved blades provide a variety ofadvantages, including greater access to certain sites within a patientas well as improved visibility during use. While curved blades, whenoperatively connected to a longitudinally vibrating transducer (e.g.,via an elongate waveguide) will generally vibrate in at least onenon-longitudinal direction (e.g., transversely) due to the asymmetricalnature of the curved blade with respect to the longitudinal axis of thewaveguide, such non-longitudinal vibrations in the blade during use canbe advantageous. For example, some curved blades that vibrate in atleast one non-longitudinal direction may provide greater bladedisplacement, particularly at the distal end of the blade.

It is also desirable in some instances to provide an ultrasonic surgicalblade having a hook-shaped blade for use in, for example, dissectingtissue. Such blades typically have a single, hook-shaped blade along oneside of the blade. One such hooked blade is shown and described in U.S.Pat. No. 5,324,299 (“the '299 Patent”), issued Jun. 28, 1994 andincorporated by reference herein. As discussed in the '299 Patent, suchhooked blades are useful for cutting loose, unsupported tissue since thehook-shaped blade is able to grasp and tension the loose tissue, therebycutting and coagulating the tissue. The hook portion is only provided onone side of the blade, and the remainder of the blade is flat, therebylimiting the usefulness of the blade.

Furthermore, curved or hooked blades can be difficult to manufacture.For example, curved blades of the prior art typically have one or morefaces (i.e., surfaces) which are curved in two or more directions, thusrequiring the use of specialized equipment such as angled chamfer endmills (also referred to as milling cutters), multiple types of end millsand precise depth-of-cut (Z-axis) control of the milling machine inorder to obtain precise blade (i.e., “end effector”) geometry. Whilesimpler straight, non-hooked blades are easier to fabricate, allowingthe use of less complex machining processes, these blades do not providethe benefits of a curved and/or hooked blade geometry.

While a variety of devices and techniques may exist for providing curvedultrasonically driven blades, it is believed that no one prior to theinventor has made or used an invention as described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

While the specification concludes with claims particularly pointing outand distinctly claiming the invention, it is believed that the inventionwill be better understood from the detailed description of certainembodiments thereof when read in conjunction with the accompanyingdrawings. Unless the context indicates otherwise, like numerals are usedin the drawings to identify similar elements in the drawings. Inaddition, some of the figures may have been simplified by the omissionof certain elements in order to more clearly show other elements. Suchomissions are not necessarily indicative of the presence or absence ofparticular elements in any of the exemplary embodiments, except as maybe explicitly stated in the corresponding detailed description.

FIG. 1 depicts a partial cross-sectional view of one embodiment of anultrasonic surgical device having a double hook curved blade.

FIG. 2 depicts one embodiment of an ultrasonic generator and attachedtransducer with which the ultrasonic surgical device of FIG. 1 can beused.

FIG. 3 depicts a perspective view of a modified version of theultrasonic surgical device of FIG. 1, wherein the waveguide has beenmodified from that depicted in FIG. 1.

FIG. 4 depicts top plan view of the waveguide and blade of FIG. 3.

FIG. 5 depicts a top perspective view of the blade and a portion of thewaveguide of the ultrasonic surgical device of FIG. 1.

FIG. 6 depicts a side view of the embodiment shown in FIG. 5.

FIG. 6A depicts a cross-sectional view of a portion of the blade shownin FIG. 6, taken along the line 6A-6A thereof.

FIG. 7 depicts a bottom perspective view of the embodiment shown in FIG.5.

FIG. 8 depicts an end view of the embodiment shown in FIG. 5.

FIG. 9 depicts a bottom plan view of the embodiment shown in FIG. 5.

FIG. 10 depicts a top plan view of the embodiment shown in FIG. 5.

FIG. 11 depicts a schematic illustration of the curvature of the firstand second faces of the blade shown in FIG. 6.

FIGS. 12-15, 17 and 18 depict a method of manufacturing the bladeportion of the embodiment of FIG. 5.

FIG. 16 depicts a schematic illustration of the curvature of the firstand second faces of an alternative embodiment of a double hook curvedblade.

FIG. 19A depicts a schematic side view of an ultrasonic shears device.

FIG. 19B depicts a partial cross-sectional view of the ultrasonic shearsdevice of

FIG. 19A.

The drawings are intended to illustrate rather than limit the scope ofthe present invention. Embodiments of the present invention may becarried out in ways not necessarily depicted in the drawings. Thus, thedrawings are intended to merely aid in the explanation of the invention.Thus, the present invention is not limited to the precise arrangementsshown in the drawings.

DETAILED DESCRIPTION

The following detailed description describes examples of embodiments ofthe invention solely for the purpose of enabling one of ordinary skillin the relevant art to make and use the invention. As such, the detaileddescription and illustration of these embodiments are purelyillustrative in nature and are in no way intended to limit the scope ofthe invention, or its protection, in any manner. It should also beunderstood that the drawings are not to scale and in certain instancesdetails have been omitted, which are not necessary for an understandingof the present invention.

Embodiments of the present disclosure provide a double hook curved bladefor use with an ultrasonic transducer for medical purposes. The bladesdescribed herein are not only curved, but also have concave hookportions located on opposite sides of the blade. The double hook curvedblades described herein provide a plurality of edges suitable forcutting tissue, in some embodiments including cutting edges havingangles that vary along the length of the cutting edge for facilitatingcutting and coagulating tissue. The double hook curved blades areprovided at the distal end of a waveguide, and have a curved portionthat extends lengthwise along at least a portion of the length of theblade and concave hook portions located on opposite sides of the curvedportion of the blade. In some embodiments, the curved portion of theblade is provided by a pair of opposing first and second faces of theblade that are flat across their widths and curved along at least aportion of their respective lengths. In some instances, a clamp memberis operatively located adjacent to the curved blade for selectiveengagement with a face of the blade so as to provide for bothcoagulating and cutting, thus providing a surgical forceps arrangement(also referred to as ultrasonic shears). With or without an associatedclamp member, the cutting blade may be used for ultrasonically cutting,coagulating and/or dissecting tissue.

The double hook curved blade embodiments described herein are configuredso as to simplify fabrication, while still providing a plurality ofblade edges suitable for cutting tissue. By providing a plurality ofblade edges, including variably angled edges, embodiments describedherein allow surgeons to employ a greater range of techniques andeffects. In addition, curved blade embodiments described herein alsoallow for tissue cutting in more than one direction, often without thesurgeon having to reposition the device.

FIG. 1 is a partially cross-sectional view of one embodiment of anultrasonic surgical device (10) comprising an elongate waveguide (12)and a double hook curved blade (24). In the particular embodiment shown,ultrasonic surgical device (10) also includes a sheath assemblycomprising a hollow cylindrical sheath (60) and a sheath coupler (70) atthe proximal end of the sheath (60). In other embodiments, the sheathassembly is omitted.

In the embodiment shown in FIG. 1, the waveguide (12) is located withinthe sheath (60) and sheath coupler (70). However, the sheath assembly isnot secured directly to the waveguide (12). Instead, and as detailedbelow, waveguide (12) is operatively attachable at its proximal end toan ultrasonic transducer, and sheath coupler (70) is secured to thetransducer housing. It will be understood, however, that waveguide (12)may be secured to the sheath assembly (i.e., to sheath (60) and/orsheath coupler (70)), such as by welding, adhesive attachment or inother ways known in the art.

The waveguide (12) includes an internally threaded connector portion(14) at its proximal end, as well as a plurality of flats (16) arrayedabout the circumference of the waveguide (12) adjacent to connectorportion (14). The flats (16) provide an integral nut on waveguide (12)for use in tightening the waveguide onto a transducer, as explainedbelow. While waveguide (12) is depicted as being of unitaryconstruction, in alternative embodiments waveguide (12) comprises two ormore portions joined to one another (e.g., by threaded attachment). Forexample, in one alternative embodiment, connector portion (14) and flats(16) comprise a unitary structure which is threadably attached at theproximal end of waveguide (12) (e.g., by use of an internally threadedbore and a mating threaded stud connecting the two portions of thewaveguide (12)). Similarly, although blade (24) is depicted as beingintegral with waveguide (12), in alternative embodiments the blade (24)is a separate structure that is attached to the distal end of waveguide(12), such as by threaded attachment.

FIG. 2 illustrates an exemplary generator (80) and ultrasonic transducer(82) with which the ultrasonic surgical device (10) may be used. It willbe understood that generator (80) and transducer (82) are merelyexemplary, as ultrasonic surgical device (10) can be used with any of avariety of generators and transducers. Transducer (82) includes ahousing (84) which is configured to facilitate grasping and manipulationof the transducer housing (84) by a medical practitioner. The proximalend of the housing (84) includes an electrical connector (e.g., a plugor a socket) for operative connection to the generator (80) via a matingconnector (81) provided at the end of a cable similarly connected to thegenerator (80). Thus, an electrical drive signal comprising analternating current of ultrasonic frequency is supplied from thegenerator (80) to the transducer (82) via the cable and connector (81).Transducer (82) converts the drive signal into a standing, ultrasonicvibrational wave in the transducer, including the distal portion (85) ofthe transducer horn (or velocity transformer, not shown) which protrudesfrom the distal end of housing (84). The transducer housing (84) alsoincludes a threaded projection (89) at its distal end, adjacent distalportion (85) of the transducer horn.

A threaded mounting stud (88) is secured to the distal portion (85) ofthe transducer horn, such as by being threadably and adhesively securedwithin a threaded bore (not shown) in distal portion (85). Thus,threaded stud (88) extends distally away from the distal end wall (86)of distal portion (85). It should also be pointed out that the distalend wall (86) of distal portion (85) of the transducer horn is locatedat an antinode of the standing vibrational wave produced by thetransducer (82). By way of example, generator (80) and transducer (82)in the depicted embodiment are configured to generate a standingvibrational wave having a frequency of about 55 kHz. However, variousother ultrasonic frequencies may be employed, such as between about 20and about 120 kHz.

Ultrasonic surgical device (10) may be operatively coupled to thetransducer (82) in a variety of ways. In the embodiment shown, connectorportion (14) at the proximal end of the waveguide (12) includes athreaded bore (17) that extends inwardly (i.e., distally) from theproximal end wall (15) of connector portion (14). Threaded bore (17) issized and configured to threadably receive mounting stud (88) oftransducer (82) therein for operatively coupling the waveguide (12) tothe transducer (82). When connector portion (14) is threaded onto themounting stud (88) of the transducer (82), the proximal end wall (15) ofconnector portion (14) is in abutment with the distal end wall (86) ofdistal portion (85) of transducer (82). When coupled in this manner, thestanding vibrational wave produced in the transducer is propagated alongthe length of the waveguide (12). Flats (16) are used to further tightenthe waveguide (12) onto the distal end of the transducer (82), and atorque wrench (not shown) may be used to ensure that the waveguide isnot over tightened.

As mentioned previously, the sheath assembly comprises cylindricalsheath (60) and sheath coupler (70), which are affixed to one another asshown. The sheath (60) may be affixed to the sheath coupler (70) in avariety of ways such as by welding, adhesive and/or swaging. In theexemplary embodiment shown in FIG. 1, a proximal portion (61) of sheath(60) is secured within a suitably configured cavity within coupler (70),adjacent the distal end of the coupler. Also, the inner diameter ofproximal portion (61) of sheath (60) is larger than the inner diameterof the portion of sheath (60) external to the coupler (70) in order toreceive the connector portion (14) and flats (16) of waveguide (12)within proximal portion (61).

Sheath coupler (70) is generally hollow and includes a threaded cavity(72) extending inwardly away from proximal end wall (74) of the coupler(70). Once the waveguide (12) has been operatively coupled to thetransducer (82) in the manner described previously, the sheath assemblyis slid over the waveguide (12). In particular, blade (24) is insertedthrough the threaded cavity (72) followed by waveguide (12). Thereafter,sheath coupler (70) is threadably secured to the transducer housing (84)by the threaded engagement of threaded projection (89) within threadedcavity (72), with the proximal end wall (74) of the coupler (70) inabutment with the end wall (87) of transducer housing (84). Onceassembled in this manner, at least a portion of blade (24) extendsbeyond the distal end wall (62) of sheath (60), as seen in FIG. 1. Inother words, in some embodiments, a proximal portion of the blade(including proximal portions of the first and second opposed faces,described further herein) is positioned within the sheath, while adistal portion of the blade extends beyond the distal end wall of thesheath (as depicted in FIG. 1). Of course, it will be understood thatthe waveguide (12), blade (24), and/or sheath assembly can be configuredsuch that either more or less of the blade (24) extends beyond thedistal end (62) of sheath (60) than is depicted in FIG. 1 (see, e.g.,FIGS. 19A and 19B). In general, enough of blade (24) should protrudebeyond the distal end of sheath (60) to provide adequate visualization,reach, and manipulation of the blade for cutting, dissection andcoagulation during use, while not having so much of the blade (24)exposed that there is a heightened risk of unintended contact betweenthe blade (24) and tissue.

In the embodiment shown in FIG. 1, between about 0.5 and about 2.5 cm ofblade (24) extends beyond the distal end wall (62) of sheath (60). Inother embodiments, between about 1.0 and about 2.0 cm of blade (24)extends beyond the distal end wall (62) of sheath (60). In still furtherembodiments, about 15% to about 85% of the distal ¼ wave, or about 30%to about 70% of the distal ¼ wave of the blade (24) is exposed. Thedistal ¼ wave is the region extending between the most distalvibrational node and the distal tip (26) of the blade—i.e.,approximately the length of the blade (24) which extends fromapproximately the most distal node to the distal tip (26).

During use of the ultrasonic surgical devices and blades describedherein, various forces applied at the blade (24) will tend to causelateral deflection of the waveguide (12) within the sheath (60). Inorder to prevent contact between the inner wall of sheath (60) and blade(24) and waveguide (12), thereby limiting or preventing potential damageto the ultrasonic device (10) as well as damping of the standing wave,one or more spacers are provided between the waveguide (12) and theinterior of sheath (60) in order to maintain the waveguide (12) in thecenter of the sheath (60) (i.e., the longitudinal axis of the waveguide(12) aligned with the longitudinal axis of the sheath (60)). In theembodiment shown in FIG. 1, resilient rings (17A, 17B) are provided onthe exterior of waveguide (12), and comprise, for example, siliconerings. Since the amplitude of the longitudinal vibration of thewaveguide (12) at the driving frequency (e.g., 55 kHz) during use iszero at the nodes of the standing wave, the resilient rings (17A, 17B)are located at or near the vibrational nodes of the waveguide (12) inorder to limit damping of the standing wave. Rings (17A, 17B) also dampany vibrations having frequencies other than the drive frequency, sincethe nodes of vibrations of other frequencies will generally not coincidewith the node locations for the drive frequency.

Resilient rings (17A, 17B) can be supported and maintained in place in avariety of ways known to those skilled in the art. For example, annularsupports for the resilient ring can be provided on the waveguide, andthe resilient ring can be, for example, insert molded over the supportor secured over the annular support in other ways known to those skilledin the art (e.g., adhesively, bonding, etc.). Annular supports can beformed, for example, by lathe turning. As yet another alternative,circumferential grooves can be provided on the waveguide (e.g., by latheturning so as to form two adjacent rings with the groove locatedtherebetween). The resilient ring can then be maintained in positionmechanically by trapping the ring within the groove. In someembodiments, resilient rings (17A, 17B) are provided at or near two ormore vibrational nodes, depending in part on the length of thewaveguide.

As is known to those skilled in the art, a variety of other features maybe provided on the waveguide (12). For example, waveguide (12) shown inFIG. 1 includes a plurality of segments of varying diameter, with tapers(18A, 18B, 18C) providing a smooth transition between segments ofdifferent diameters. In the exemplary embodiment shown in FIG. 1, firstsegment (12A) is located adjacent flats (16) and has a diameter smallerthan that of the flats (16) region in order to amplify the standingvibrational wave. A first taper (18A) is located at the distal end offirst segment (12A), and provides a smooth transition from the largerdiameter of first segment (12A) to the smaller diameter of secondsegment (12B). Similarly, a second taper (18B) is located at the distalend of second segment (12B), and provides a smooth transition from thesmaller diameter of second segment (12B) to the larger diameter of thirdsegment (12C). Finally, a third taper (18C) is located at the distal endof third segment (12C) (adjacent resilient ring (17B), at themost-distal vibrational node of the waveguide), and provides a smoothtransition from the larger diameter of third segment (12C) of waveguide(12) to the smaller diameter of the blade (24). These changes indiameter serve to, among other things, adjust the amplitude and/orfrequency of the vibrational wave propagating the length of thewaveguide. It will be understood, however, that this is merely oneexemplary arrangement of the waveguide. Alternative embodiments includeany number of segments of varying diameters, depending, in part, on thedesired length of the waveguide (which will depend, for example, on theintended use of the instrument).

In the modified version of the waveguide (412) shown in FIGS. 3 and 4,four tapers (418A-418D) are provided on the waveguide (412). Inaddition, a pair of flats (419) are provided on opposite sides of thewaveguide (e.g., by milling). As is known to those skilled in the art,flats (419) are used to damp any vibrations having frequencies otherthan the drive frequency (also referred to as parasitic vibrations).

The ultrasonic surgical device comprising waveguide (12) and blade (24)can be made from any of a variety of materials, particularly variousmedically and surgically acceptable metals such as titanium, titaniumalloy (e.g., Ti6A14V), aluminum, aluminum alloy, or stainless steel. Thewaveguide (12) and blade (24) shown in FIG. 1 are formed as a singleunit, fabricated from a single metal rod that has been milled so as toprovide the depicted features. Alternately, the waveguide and blade maycomprise two or more separable components of the same of differingcompositions, with the components coupled to one another by, forexample, adhesive, welding, a threaded stud, and/or other suitable waysknown to those skilled in the art. For example, waveguide (12) may beconfigured as two pieces joined together at or between flats (16) andfirst segment (12A). Similarly, blade (24) may be constructed separatelyfrom waveguide (12) and joined to the distal end of waveguide (12).

It will also be understood that the ultrasonic surgical devicecomprising waveguide (12) and blade (24) may be used without the sheathassembly simply by operatively coupling the proximal end of thewaveguide (12) (i.e., connector portion (14)) to transducer (82) (viathreaded mounting stud (89)). Sheath (60), however, not only protectsthe waveguide (12), but also prevents inadvertent contact between thewaveguide (12) and the patient, medical personnel or the surgicalenvironment. Not only will such contact damp vibration of the waveguide(12), but it can also cause injury to the patient or medical personnelsince the waveguide (12) is ultrasonically vibrating.

As mentioned previously, the blades depicted and described herein arenot only curved, but also have concave hook portions located on oppositesides of the blade. The double hook curved blades described hereinprovide a plurality of edges suitable for cutting tissue, includingvarying edge angles for facilitating cutting and coagulating tissue.These blades can be fabricated from round stock using only simple latheturning and end mills, with no Z-axis milling, while still providing aplurality of blade edges suitable for cutting tissue.

The double hook curved blades depicted and described herein are providedat the distal end of a waveguide, and have a curved portion that extendslengthwise along at least a portion of the length of the blade andconcave hook portions located on opposite sides of the curved portion ofthe blade. In some embodiments, the curved portion of the blade isprovided by a pair of opposing first and second faces of the blade thatare flat across their widths, which width extends perpendicular to theprojected longitudinal axis (L) of the waveguide (see FIG. 4). Alongtheir respective lengths (i.e., the direction orthogonal to theirrespective widths), each of the first and second curved faces includesone or more curved segments, with each of the curved segments of anindividual face being curved in the same direction (however, thatcurvature can be positive and/or negative curvature). In theseembodiments, the direction of curvature of the curved segments of thefirst and second opposed faces does not change along their respectivelengths, with the curvature gradient on the surface of each face beingnon-zero in one direction (for the curved segments of each face) andzero in the perpendicular direction (i.e., across their widths). Thus,the axes of curvature of each of the curved segments of an individualface are parallel to one another (as seen, for example, in FIG. 5). Inaddition, the axes of curvature of each of the curved segments of thefaces of the blade is perpendicular to a plane which includes thelongitudinal axis (L) of the waveguide (i.e., the faces of the bladeinclude no curved segment having an axis of curvature which is notperpendicular to a plane which includes the longitudinal axis of thewaveguide).

Accordingly, in those embodiments wherein the curved portion of theblade is provided by a pair of opposing first and second faces of theblade that are flat across their widths and curved along their lengthsin a single direction, the first and second faces comprise developablesurfaces, thereby facilitating the manufacture of the blade from roundstock using an end mill and only X- and Y-axis movement of the workpiece(i.e., the blade material, e.g., round stock) and mill with respect toone another. No Z-axis movement or cutting is required during millingthe first and second faces, since each is flat and/or includes one ormore right cylindrical surfaces (circular or elliptic cylindricalsurfaces). (The configuration of the blade faces described by theforegoing may be better understood with references to the method ofproducing the blade faces from round stock, as further describedherein.)

The first and second opposing faces are spaced apart from one anotheralong their lengths, with the blade having sidewalls comprisingcylindrical surfaces extending between the first and second faces alongeither side of the blade. As used herein, unless the context indicatesotherwise, the term cylindrical surface includes not only a portion ofthe surface of a right circular cylinder, but also a portion of thesurface of a tapered or elliptical cylinder (e.g., the blades describedherein can be fabricated from any turned stock, including not onlystraight or tapered cylindrical stock but also straight or taperedelliptical turned stock).

The intersections between each of the first and second faces and each ofthe sidewalls define blunt cutting edges, which extend along at least aportion of the length of the blade (e.g., a portion of the length of thefirst and second opposed faces of the blade). Because each of the firstand second blade faces is not necessarily curved in the same manner, avariety of cutting edge shapes and configurations can be provided on thesame blade in order to give more cutting options to the medicalpractitioner.

Furthermore, in embodiments further described herein and depicted in thefigures, the axes of curvature for the curved portions of the first andsecond faces are parallel to one another—i.e., the first and secondfaces curve in the same direction (although that direction of curvaturecan be positive or negative on different portions of each face). This isbest seen, for example, in FIG. 11 which depicts a side plan view ofblade (24) (the same view as FIG. 6), which shows the curvatures of thefirst and second blade faces. As a result, even though the blade maytaper in thickness along portions of its length, the cross-sectionalshape of the blade in any plane perpendicular to the longitudinal axisof the waveguide through the first and second faces of the blade is asdepicted in FIG. 6A. This cross-sectional shape, similar to a stadium ordiscorectangle, comprises four sides—a pair of flat, parallel sides(i.e., the opposing first and second faces), and a pair of opposedcurved sides (i.e., the cylindrical surface sidewalls). It will beunderstood, however, that since the curvature of the first and secondfaces is not necessarily the same throughout the blade (i.e., the bladecan be tapered), the flat, parallel sides of a cross-section through thefirst and second faces of the blade are not necessarily of the samewidth. This can be seen, for example, in FIG. 6A wherein the first, orupper face 28 is wider than the second, or lower face 30. FIGS. 9 and 10also depict how the widths of the first and second faces (28, 30) arenot identical to one another at every point along the length of theblade, as well as not having a constant width along their respectivelengths.

The concave hook portions located on opposite sides of the blade canextend inwardly into the cylindrical surface sidewalls of the blade,formed, for example, by advancing a rotating end mill into each sidewallof the blade. When formed in this manner, the cross-sectional shape ofthe blade in any plane perpendicular to the longitudinal axis of thewaveguide through the hook portions may comprise, for example, arectangle or a trapezoid (if hook portions are cut at an angle).

Alternatively, and as further described below, in some embodiments eachof the concave portions comprises a portion of an outwardly curved(i.e., concave) surface of revolution, such as a portion of the surfaceof a circular hyperboloid (i.e., a “hyperboloidal surface”) extendingbetween the first and second faces of the blade, wherein the axis of thesurface of revolution coincides with the longitudinal axis (L) of thewaveguide. In this instance, the cross-sectional shape of the blade inany plane perpendicular to the longitudinal axis of the waveguidethrough the hook portions will be the same as that shown in FIG. 6A,with the flat, parallel sides of the cross-section not necessarily ofthe same width. In fact, when the first and second faces (28, 30) havedifferent widths (as shown in FIGS. 9 and 10), the angle between thefirst face (28) and the interior surface (42) of each hook portion willbe different than the angle between the second face (30) and theinterior surface (42) of the hook portions. This feature providesdifferent angles for the cutting edge at the intersection of each hookportion and the first face and the cutting edge at the intersection ofeach hook portion and the second face. As noted below, this arrangementwherein the hook portions comprise hyperboloidal surfaces (or portionsof other outwardly curved surfaces of revolution) also facilitates thefabrication of the blade from round stock using simple lathe turning toprovide the hyperboloidal surface and end mills to produce the first andsecond faces of the blade.

In addition, because the hook portions are identical to one another andare located on opposite sides of the blade, the blade embodimentdepicted in the drawings is also symmetrical with respect to a planethat includes the longitudinal axis (L) of the waveguide (i.e., a planeorthogonal to the plane of FIGS. 9 and 10). Because of this as well asthe curvature of the blade, the blade will vibrate both longitudinallyand transversely (i.e., in the X- and Y-directions of FIG. 17, but notin the Z-direction).

Turning to the specific embodiment of a blade (24) depicted in FIGS.5-11, the proximal end of the blade (24) (i.e., the portion of the bladeadjacent the waveguide (12)) comprises a cylindrical portion (25)located between the distal end of the waveguide (12) and the curvedportion of the blade. Cylindrical portion (25) is thus located betweenthe taper (18C) (typically adjacent the most-distal node of thewaveguide) and the proximal ends of first and second faces (28, 30)(also referred to herein as the upper and lower faces, respectively). Inalternative embodiments, no such cylindrical portion is included on theproximal end of the blade.

First and second opposed faces (28, 30) are located on opposite sides ofthe blade (24), extending distally away from cylindrical portion (25) todistal tip (26). In this particular embodiment, first (or upper) face(28) is flat across its width and curved (in a single direction) alongits length, wherein its width is defined as extending perpendicular tothe projected longitudinal axis (L) of the waveguide (see FIG. 5) andits length extends orthogonal to its width (i.e., parallel to thelongitudinal axis (L)). In the embodiment shown, first face (28) iscontinuously curved along its entire length, having a positive,elliptical curvature (as best seen in FIG. 11). As used herein, the axisof curvature of an elliptically curved surface, such as first and secondfaces (28, 30) whose curvature is defined by an ellipse (D, G) in FIG.11, is defined as a line extending through center point (H) parallel tothe width of the first and second faces and perpendicular to thelongitudinal axis (L). The axis of rotation of other complex curves canbe similarly defined. As also used herein, a concave surface has apositive curvature, while a convex surface such as the distal segment(30B) of second face (30) has a negative radius of curvature.

Along its length, the curvature of first face (28) follows a portion ofan ellipse (D) that is tilted with respect to the longitudinal axis (L)of the waveguide (12). Thus, as seen in FIG.11, the major axis (E) ofellipse (D) is not parallel to the longitudinal axis (L), but rather istilted at an included angle of about 5 degrees. Of course the ellipticalpath of first face (28) need not be tilted with respect to thelongitudinal axis (L) or may be tilted to varying degrees (e.g., up toabout 20 degrees, or between about 2 and about 10 degrees). It will alsobe understood that first and second faces (28, 30) can be curved in anyof a variety of manners, such as having a single, uniform radius ofcurvature (i.e., a surface that follows a portion of a circular path), aconstantly varying radius of curvature along its entire length (or aportion thereof), or segments of varying curved shapes and/or curvatureincluding one more segments that are flat across both their width andlength. However, in the depicted embodiments, the direction of curvatureof the first and second opposed faces does not change along theirrespective lengths, such that the axes of curvature of each of thecurved portions of the first and second faces are parallel to oneanother (as seen, for example, in FIG. 11). In addition, the axes ofcurvature of each of the curved portions of the first and second faces(28, 30) of the blade are perpendicular to a plane which includes thelongitudinal axis (L) of the waveguide (i.e., the faces of the bladeinclude no curved portion having an axis of curvature which is notperpendicular to a plane which includes the longitudinal axis of thewaveguide).

Second (or lower) face (30) is also flat across its width and curved (ina single direction) along its length. In the depicted embodiment,however, second face (30) includes a positively curved (concave)transition segment (30A) and a negatively curved (convex) distal segment(30B). Transition segment (30A) provides a smooth transition fromcylindrical portion (25) to the distal segment (30B) of the curvedportion of the blade. Not only is transition segment (30A) of secondface (30) necessitated by the use of an end mill to form the blade facesin turned stock, the transition segment (30A) helps to reduce stress atthe intersection of the second face (30) and the cylindrical portion(25). Nevertheless, the transition segment (30A) as well as the edges(35A) between transition segment (30A) and the cylindrical surfacesidewalls (34) extending between the first and second faces (28, 30) arealso usable portions of the blade. Thus, for example, edges (35A), likeedges (35B) between distal segment (30B) and sidewalls (34), can be usedfor cutting and/or cauterizing tissue.

Transition segment (30A) as well as distal segment (30B) of second face(30) are flat across their widths and curve in a single direction alongthe length of second face (30). In the embodiment shown, the curvatureof transition segment (30A) follows a portion of a circle (F) (see FIG.11). Once again, however, the axis of curvature of transition segment(30A) (i.e., the center of circle (F)) is parallel to the axes ofcurvature of first face (28) (i.e., the foci of ellipse (D)), and isperpendicular to a plane which includes the longitudinal axis (L) of thewaveguide. The curvature of distal segment (30B), on the other hand, isnot only negative (i.e., distal segment (30B) is convex), it follows aportion of an ellipse (G) that, like ellipse (D), is tilted with respectto the longitudinal axis (L) of the waveguide (12). In fact, althoughmerely exemplary of one embodiment, ellipses D and G are concentric(i.e., have a common center point (H) and major and minor axes).However, since the eccentricity of ellipse (G) is less than that ofellipse (D), the distance between first face (28) and second face (30)decreases along their lengths such that the blade (24) is slightlytapered. It will be understood, of course, that a variety of othercurvatures (e.g., a non-tilted ellipse) may be used for the curvature ofone or both of the first and second faces (28, 30), as desired.

It should be noted that, although the first and second faces (28, 30)are flat across their respective widths, these surfaces appear to beslightly curved across their widths in the end view of FIG. 8. However,this apparent curvature in FIG. 8 is simply the result of distal end(26) being curved (further described below), combined with thelongitudinal curvature of the first and second faces (28, 30). In analternative embodiment, distal end (26) is flat (see, e.g., FIG. 14),and in such an embodiment an end view like that of FIG. 8 would notappear to show widthwise curvature of the first and second blade faces.

As mentioned previously, the first and second opposing faces (28, 30)are spaced apart from one another along their lengths by cylindricalsurface sidewalls (34) extending between the first and second facesalong either side of the blade (24) between the proximal ends (29, 31)of the first and second faces (28, 30) and the proximal ends (37) of theconcave hook portions (36) located adjacent the distal end (26) of blade(24). The intersections between each of the first and second faces (28,30) and the sidewalls (34) define blunt cutting edges (33, 35) thatextend along at least a portion of the length of the blade. Due to, forexample, the tilting of, and eccentricity differences between, ellipsesD and G and the resulting differences in curvature of the first andsecond faces (28, 30), as well as the fact that one face is concave andthe other convex, the bluntness (i.e., angle) of the cutting edges (33,35) vary independently along their respective lengths. This aspect ofblade (24), as well as other embodiments of such double hook curvedblades, provide a plurality of cutting options to the medicalpractitioner in order to meet the needs of a particular medicalprocedure and/or patient. For example, different cutting and/orcoagulating properties can be obtained simply by rotating or otherwisemoving the position of the blade so as to employ any of the variety ofcutting edges, edge angles and surfaces provided by the blade (24).

Concave hook portions (36) are located adjacent the distal end (26) ofblade (24), on opposing sides of the blade. The concave hook portions(36) extend between the first and second faces (28, 30), flaringoutwardly from the sidewalls (34) along the length of the hook portions.Thus, the proximal ends (37) of the hook portions (36) generally havethe same diameter, and even the same circumferential curvature, as thedistal end of sidewalls (34). Although the distal end (38) of hookportions (36) can extend to the distal end (26) of the blade (24), inthe embodiment shown the distal end (38) is spaced slightly from distalend (26) such that a pair of surfaces (39) are located between thedistal ends (38) of hook portions (36) and the distal end (26) of theblade. In the depicted embodiments, surfaces (39) comprise cylindricalsurfaces similar to, but greater in diameter than sidewalls (34) andcylindrical portion (25) at the proximal end of the blade (see, e.g.,FIGS. 9 and 10).

Each of the concave hook portions (36) comprises a portion of anoutwardly curved (i.e., concave) surface of revolution, such as aportion of the surface of a circular hyperboloid (i.e., a “hyperboloidalsurface”), extending between the first and second faces (28, 30) of theblade. The axis of rotation of the outwardly curved surface ofrevolution coincides with (i.e., is the same as) the longitudinal axis(L) of the waveguide (12), as will be apparent from the description ofhow the hook portions (36) are fabricated. Thus, a pair of curvedcutting edges (40) are provided along the intersection of first face(28) and the concave surface of revolution (e.g., a hyperboloidalsurface) of each hook portion (36). Likewise, a pair of curved cuttingedges (41) are provided along the intersection of second face (30) andthe concave surface of revolution of each hook portion (36).

As will be apparent, each of the curved cutting edges (40, 41) not onlycurves in the same direction of curvature of the first and second faces(28, 30) (e.g., elliptically upward when viewed from the side), but alsocurves outwardly away from the longitudinal axis of the waveguide. Forexample, when concave hook portions comprise portions of a circularhyperboloid, the curved cutting edges curve about an axis (J) (see FIG.11) that is orthogonal to both the longitudinal axis (L) as well as theaxes of curvature of the first and second faces (28, 30). (Technically,the axis J is a focal point of the hyperbola whose surface of revolutiondefines the hyperboloidal surface of the hook portions.) Furthermore,since the interior surface (42) of each hook portion (36) comprises ahyperboloidal surface (or other concavely curved surface of revolution)with an axis of revolution coinciding with the longitudinal axis (L) ofthe waveguide (12), the interior surface (42) of each hook portion (36)is curved about the longitudinal axis (L). As a result, the cuttingedges defined by the intersection of the first and second faces (28, 30)with the hook portions (i.e., interior surface (42)) not only curves andvaries in angle along their respective lengths, the upper hook cuttingedges (40) (i.e., the intersection of the first face (28) with the hookportions) are not identical to the lower hook cutting edges (41). Forexample, the angle of the upper hook cutting edge (40) at any givenpoint along the length of the hook portion of the blade can be differentfrom the angle of the lower hook cutting edge (41). In the exampleshown, since the second face (30) is wider than the first face (28)throughout the length of the hook portion of the blade, the angle of thelower hook cutting edge (41) is smaller than the angle of the upper hookcutting edge (40) (i.e., the lower hook cutting edge (41) is sharper).Nevertheless, as explained below, the blade (24), including concave hookportions (36), is readily fabricated from turned stock using simplelathe turning to provide the hyperboloidal surface (or other concavelycurved surface of revolution) and end mills to produce the first andsecond faces of the blade.

The distal end (26′) of the blade (24) can be flat, as shown in FIG. 14,or curved as shown in FIGS. 3-10 and 15. Curved distal end (26) providesadditional cutting and coagulating properties and options for thesurgeon, as do cylindrical surfaces (39) between the distal end (38) ofthe hook portions (36) and the distal end (26) of the blade.

As mentioned previously, in alternative embodiments the opposed firstand second faces of the blade can have segments of varying amounts ofcurvature, but still with the axes of curvature for the curved segmentsparallel to one another—i.e., the first and second faces curve in thesame direction (although that direction of curvature can be positive ornegative on different portions of each face). Such an alternativeembodiment is depicted in FIG. 16, wherein blade (224) has first andsecond faces (228, 230, each having a plurality of segments of varyingcurvature (but all of the curved segments curving in the same direction,and flat across their widths).

Thus, first face (228) includes a proximal (or transition) segment(228A) concavely curved about a portion of a first circle (M), anintermediate flat segment (228B) having no curvature, and a distalsegment (228C) concavely curved about a portion of a second circle (N)having a larger radius than the first circle (M). Similarly, second face(230) includes a proximal (or transition) segment (230A) (similar totransition segment (30A) that is concavely curved about a portion of athird circle (S), an intermediate flat segment (228B) having nocurvature, and a distal segment (228C) convexly curved about a portionof a fourth circle (T) having a larger radius than the third circle (S).The hook portions of blade (224) are similar to hook portions (36) ofthe previously described embodiment. It will be understood that anynumber of segments can be provided on the first and second faces of thedouble hook curved blades, some of which can be flat (either parallel ortapered with respect to the longitudinal axis of the waveguide), whileothers are curved (e.g., about a portion of a circle or ellipse). Ingeneral, at least one segment of each of the first and second faces iscurved (i.e., has a non-zero curvature gradient), in particular at leastthe distal most segments of each of the first and second faces (i.e.,the portion of the first and second faces immediately adjacent to thehook portions of the blade).

In addition, in most embodiments the second face has a concavely curvedtransition segment extending distally away from the proximal end of thesecond face, and a convexly curved distal segment extending proximallyaway from the distal end of the second face. The first face in theseembodiments, on the other hand, has only concavely curved or flatsegments, such as a continuous curvature along its entire length (e.g.,first face (30)) or at least a concavely curved distal segment extendingproximally away from the distal end of the first face.

FIGS. 12-15 depict a method of manufacturing blade (24) from a segment(44) of round stock, wherein only a portion of waveguide (12) is shownfor purposes of clarity. Starting from a single round stock (e.g., acylindrical rod), the omitted features of waveguide (12) (e.g., tapers(18)) are formed by methods known to those skilled in the art. Inparticular, the diameter of the originally round stock has been reducedin FIG. 12 to provide not only taper (18C), but also a cylindricalsection (46) having a radius corresponding to not only the desiredradius of cylindrical portion (25) but also the cylindrical surfacesidewalls (34). Taper (18C) and cylindrical section (46) can be formed,for example, by turning the original round stock on a lathe to reduceits diameter. Similarly, a hyperboloidal surface (48) (or otherconcavely curved surface of revolution) is formed adjacent the distalend of the segment (44) of round stock, optionally leaving distalcylinder (50) at the distal end of the turned stock having the samediameter as (or less than) the diameter of the original round stock.Hyperboloidal surface (48) (technically speaking, one-half of ahyperboloid of one sheet) provides the interior surfaces (42) of eachhook portion (36). Distal cylinder (50) provides the pair of surfaces(39) located between the distal ends (38) of hook portions (36) and thedistal end (26) of the blade.

Following size reduction of the round stock to the configuration shownin FIG.

12, the first face (28) of the blade (24) is machined using an end millto produce the configuration shown in FIG. 13. However, no Z-axismilling is required. For example, first face (28) is milled into theturned stock using an end mill (52) as shown in FIGS. 17 and 18. Theworkpiece (the turned stock (44)) is positioned on the X-Y table of amilling machine, as shown in FIGS. 17 and 18. The workpiece is thenadvanced in the X- and Y-directions, without rotation of the workpiece,as the end mill is spinning (about a Z-oriented axis). As a result,first face (28) is milled into the workpiece, wherein first face (28) isflat across its width (i.e., the Z-direction in FIG. 18). Second face(30) is milled in the same manner, without the need to rotate theworkpiece about its longitudinal axis (L) but rather merely moving theworkpiece in the Y-direction for reorientation prior to milling secondface (30) to produce the partially completed blade shown in FIG. 14.

(Alternatively, the workpiece may be rotated 180 degrees about itslongitudinal axis from the position shown in FIG. 18 in order to machine(mill) second face (30).)

As a result of milling first and second faces (28, 30) using end mills,hook portions (36) are provided on the blade (24), corresponding toportions of hyperboloidal surface (48) (or other concavely curvedsurface of revolution). While the blade (24) may be used in the formshown in FIG. 14, in the depicted embodiment the distal end (26) of theblade is milled such that the distal end (26) is curved (as shown inFIG. 15). In other words, the distal end (26) of the blade is roundedoff.

An alternative embodiment of an ultrasonic surgical device (110) isdepicted in FIGS. 19A and 19B, wherein the device (110) is configured asultrasonic shears (also known as a clamp coagulator or ultrasonicforceps) having a clamp member (150) pivotally supported adjacent blade(124), wherein blade (124) is similar to the double hook curved blades(24, 224) described previously herein. The clamp member (150) is adaptedfor selective engagement with a face of the blade (124) so as to providefor the simultaneous cutting and coagulation of tissue urged against theface of blade (124) by the clamp member (150). In the embodiment shown,clamp member (150) is located and configured for selective engagementwith the first (or upper) face of the blade (124).

Ultrasonic surgical device (110) is, apart from the blade (124) and theclamp member (150), similar to the apparatus shown and described in U.S.Pat. No. 5,322,055 (which is incorporated by reference herein). Like theprevious embodiment, the curved blade (124) is provided at the distalend of an elongate waveguide (112). While waveguide (112) and blade(124) are depicted as being of unitary construction, in alternativeembodiments waveguide (112) comprises two or more portions joined to oneanother (e.g., by threaded attachment). Similarly, although blade (124)is depicted as being integral with waveguide (112), in alternativeembodiments the blade (124) is of separate structure and attached to thedistal end of waveguide (112), such as by threaded attachment.Ultrasonic surgical device (110) also includes a hollow cylindricalsheath (160) in which at least a portion of waveguide (112) andoptionally a portion of blade (124) is positioned.

As in the previous embodiment, although at least a portion of thewaveguide (112) is located within the sheath (160), the sheath (160) isnot secured directly to the waveguide (12). Instead, and as detailedbelow, waveguide (112) is operatively attached at its proximal end to atransducer (182), and the proximal end of sheath (160) is secured withinthe handpiece (172).

Ultrasonic surgical device (110) further includes an ultrasonictransducer (182) mounted to the handpiece (172), as shown. Transducer(182) may be removably mounted to the handpiece (172), such as bythreaded engagement therewith, or may be fixed within or on thehandpiece (172). Transducer (182) includes a housing (184) which isconfigured to facilitate grasping and manipulation of the surgicaldevice (110) along with stationary handle (174) of handpiece (172). Theproximal end of the transducer housing (184) includes an electricalconnector (e.g., a plug or a socket) for operative connection to agenerator. Thus, an electrical drive signal comprising an alternatingcurrent of ultrasonic frequency will be supplied from the generator tothe transducer (182) via a cable operatively connected to the electricalconnector on the transducer housing. As with the previous embodiment,transducer (182) converts the drive signal into a standing, ultrasonicvibrational wave in the transducer, including the transducer horn (orvelocity transformer) (185).

Although not shown in FIGS. 19A or 19B, a threaded mounting stud issecured to the distal end (186) of the transducer horn (185), such as bybeing threadably and adhesively secured within a threaded bore in thedistal end (186) of the transducer horn (185). Thus, as in the previousembodiment, this threaded stud extends distally away from the distal end(186) of transducer horn (185), and this distal end (186) of transducerhorn (185) is located at an antinode of the standing vibrational waveproduced by the transducer (182) (e.g., at 55 kHz). Similar to theprevious embodiment, the proximal end of waveguide (112) includes athreaded bore (not shown) that extends inwardly (i.e., distally) fromthe proximal end of the waveguide (112). This threaded bore is sized andconfigured to threadably receive the mounting stud on the distal end ofthe transducer horn (185), such that the waveguide (112) is operativelycoupled to the transducer (182) by threadably securing the waveguideonto the mounting stud of the transducer horn (185). When coupled inthis manner (i.e., as seen in FIG. 19B), the standing vibrational waveproduced in the transducer (182) is propagated along the length of thewaveguide (112).

The sheath (160) may be affixed to the handpiece (172) in a variety ofways known to those skilled in the art, such as by welding, adhesive,mechanical fasteners and/or swaging. In the exemplary embodiment shownin FIGS. 19A and 19B, the proximal end of sheath (160) and the waveguide(112) are secured within handpiece (172) by a mounting pin (191).

As seen in FIG. 19A, at least a portion of blade (124) extends beyondthe distal end wall (162) of sheath (160). Once again it will beunderstood that the waveguide (112), blade (124), sheath (160) and/orhandpiece (172) can be configured such that more or less of the bladeextends beyond the distal end of sheath (160) than depicted in FIG. 19A.In this instance, the entirety of the first and second blade faces(i.e., the curved portion of the blade) extends beyond the distal endwall (162) of sheath (160). As with the previously described embodiment,one or more resilient rings (117) are provided on the exterior ofwaveguide (112) (e.g., silicone rings) and act as spacers that not onlymaintain the waveguide (112) centered with sheath (160), but also arelocated at vibrational nodes of the waveguide (112) in order to limitdamping of the standing wave at the drive frequency while also dampingfrequencies other than the drive frequency.

Clamp member (150) includes a pad (151) mounted thereto for compressingtissue against a face or edge of the blade (124) in order to facilitatethe cutting and coagulating of tissue. Pad (151) is formed of apolymeric or other compliant material, and engages the first face of theblade (124) when the clamp member (150) is pivoted to its fully closedposition. Pad (151) can comprise, for example, PTFE or polyimide (PI),with or without added filler materials such as glass, metal and/orcarbon. In some embodiments, pad (151) comprises a high temperatureresistant material. Pad (151) is attached to the clamp member (150) by,for example, an adhesive or mechanical fastener. As seen in FIGS. 19Aand 19B, the exposed surface of the pad (151) provides a curvedtissue-engaging surface. In the embodiment shown, this tissue-engagingsurface has a curvature corresponding to the curvature of thecorresponding portion of the first face of the blade.

The proximal end of the clamp member (150) is pivotally mounted to thesheath (160), adjacent the distal end thereof, by a pivot pin (153). Theclamp member (150) is also pivotally attached to the distal end of anactuator rod (179) at pivot pin (154). Actuator rod (179) is mounted tothe handpiece (172) for linear movement parallel to the longitudinalaxis of waveguide (112), and extends outwardly from the handpiece (172)directly above the sheath (160). From the open position of FIG. 19A,linear movement of the actuator rod (179) in the distal direction (i.e.,towards blade (124)), causes the clamp arm to pivot towards its closedposition, such that pad (151) will eventually engage the first face ofthe blade (124). Similarly, from the closed position, linear movement ofthe actuator rod (179) in the proximal direction (i.e., towardstransducer (182)), causes the clamp arm to pivot to its open position ofFIG. 19A.

In order to effect linear, longitudinal movement of actuator rod (179),a pivoting handle (175) is pivotally mounted to handpiece (172), asshown. Handle (175) is pivotally secured within handpiece (172) at pivotpin (176), and the distal end of handle (175) is pivotally attached tothe proximal end of actuator rod (179) at pivot pin (177) withinhandpiece (172). Thus pivotal movement of handle (175) away fromhandpiece (172) causes the clamp member (150) to pivot towards its openposition (FIG. 19A), while pivotal movement of handle (175) towardshandpiece (172) causes the clamp member (150) to pivot towards itsclosed, tissue clamping, position.

While various embodiments of ultrasonic surgical devices and bladesthereof have been described in detail above, it will be understood thatthe components, features and configurations, as well as the methods ofmanufacturing the devices and methods described herein are not limitedto the specific embodiments described herein.

1. An ultrasonic surgical device comprising: (a) an elongate waveguidehaving a longitudinal axis and a distal end; and (b) a blade extendingaway from the distal end of the waveguide, said blade having: a length,a distal end, first and second opposed faces extending lengthwise alongat least a portion of the length of the blade, and sidewalls extendingbetween the first and second faces along either side of the blade suchthat said first and second opposing faces are spaced apart from oneanother, wherein each of said first and second faces has a width thatextends perpendicular to the longitudinal axis of the waveguide and alength that extends orthogonal to said width, and a pair of hookportions, said hook portions located on opposite sides of the blade,each hook portion having a continuous interior surface that extendsbetween said first and second opposed faces; wherein each of said firstand second opposed faces is flat across its width and includes one ormore curved segments along its length, with each of the curved segmentsof an individual face being curved in the same direction such that theaxes of curvature of each of the curved segments of an individual faceare parallel to one another, and the axes of curvature of each of thecurved segments of the faces of the blade are perpendicular to a planewhich includes the longitudinal axis of the waveguide.
 2. The ultrasonicsurgical device of claim 1, wherein each of the curved segments of saidfirst and second faces are curved in the same direction such that theiraxes of curvature of are parallel to one another.
 3. The ultrasonicsurgical device of claim 1, wherein each of said hook portions has aconcave interior surface that flares outwardly from one of saidsidewalls in the distal direction.
 4. The ultrasonic surgical device ofclaim 1, wherein said sidewalls comprise cylindrical surfaces extendingbetween the first and second faces.
 5. (canceled)
 6. The ultrasonicsurgical device of claim 4, wherein the intersections between each ofthe first and second faces and each of the sidewalls define cuttingedges, and further wherein the angles of said cutting edges defined bythe intersections between each of the first and second faces and each ofthe sidewalls vary along at least a portion of the length of the cuttingedges.
 7. The ultrasonic surgical device of claim 3, wherein theinterior surface of each of said hook portions comprises a portion of aconcavely curved surface of revolution extending between the first andsecond faces of the blade.
 8. The ultrasonic surgical device of claim 7,wherein said concavely curved surface of revolution comprises ahyperboloidal surface having an axis of rotation that coincides with thelongitudinal axis of the waveguide.
 9. The ultrasonic surgical device ofclaim 3, wherein said hook portions are located adjacent the distal endof the blade.
 10. (canceled)
 11. The ultrasonic surgical device of claim3, wherein the intersections between each of the first and second facesand the interior surface of each of said hook portions define cuttingedges that curve in two directions.
 12. (canceled)
 13. The ultrasonicsurgical device of claim 11, wherein, in one or more planesperpendicular to the longitudinal axis of the waveguide, the angle ofthe cutting edges defined by the intersections between the first faceand the interior surface of each of said hook portions is larger thanthe angle of the cutting edges defined by the intersections between thesecond face and the interior surface of each of said hook portions. 14.The ultrasonic surgical device of claim 1, wherein said first facecomprises at least one curved segment having a positive curvature. 15.The ultrasonic surgical device of claim 1, wherein said first facecomprises at least one curved segment having a positive ellipticalcurvature.
 16. The ultrasonic surgical device of claim 14, wherein saidfirst face is continuously and positively curved along its entirelength.
 17. The ultrasonic surgical device of claim 15, wherein saidelliptical curvature follows a portion of an ellipse that is tilted withrespect to the longitudinal axis of the waveguide.
 18. The ultrasonicsurgical device of claim 14, wherein said second face comprises at leastone curved segment having a negative curvature.
 19. The ultrasonicsurgical device of claim 14, wherein said second face comprises at leastone curved segment having a negative elliptical curvature. 20.(canceled)
 21. The ultrasonic surgical device of claim 18, wherein saidsecond face further comprises a curved transition segment having apositive curvature, said transition segment located proximal to thecurved segment of the second face having a negative curvature. 22-23.(canceled)
 24. The ultrasonic surgical device of claim 1, wherein saidfirst face comprises an elliptically curved segment having a positiveelliptical curvature and extending to the distal end of the blade, andsaid second face comprises an elliptically curved segment having anegative elliptical curvature and extending to the distal end of theblade, wherein said elliptically curved segments of the first and secondfaces each follow portions of ellipses that are concentric with oneanother.
 25. (canceled)
 26. The ultrasonic surgical device of claim 2,wherein the thickness of the blade is smallest at its distal end.
 27. Anultrasonic surgical device comprising: (a) an elongate waveguide havinga longitudinal axis and a distal end; and (b) a blade extending awayfrom the distal end of the waveguide, said blade having: a length, adistal end, a curved portion that includes first and second opposedfaces extending lengthwise along at least a portion of the length of theblade, wherein each of said first and second faces has a width thatextends perpendicular to the longitudinal axis of the waveguide and alength that extends orthogonal to said width, and a pair of hookportions, said hook portions located on opposite sides of the blade;wherein said first and second opposed faces of the blade are spacedapart from one another along their respective lengths, the blade furthercomprising sidewalls extending between the first and second faces alongeither side of the blade and along at least a portion of the length ofthe blade, and further wherein each of said hook portions has aninterior surface comprising a portion of a surface of revolutionextending between the first and second faces of the blade, with the axisof rotation of said surface of revolution coinciding with thelongitudinal axis of the waveguide.
 28. The ultrasonic surgical deviceof claim 27, wherein each of said first and second opposed faces is flatacross its width and includes one or more curved segments along itslength, with each of the curved segments of said first and second facescurved in the same direction such that their axes of curvature areparallel to one another.
 29. The ultrasonic surgical device of claim 27,wherein each of said hook portions has a concave interior surface whichflares outwardly in the distal direction from a distal end of one ofsaid sidewalls.
 30. The ultrasonic surgical device of claim 29, whereineach of said hook portions are located along the curved portion of theblade.
 31. The ultrasonic surgical device of claim 27, wherein saidfirst face comprises an elliptically curved segment having a positiveelliptical curvature and extending to the distal end of the blade, andsaid second face comprises an elliptically curved segment having anegative elliptical curvature and extending to the distal end of theblade.
 32. The ultrasonic surgical device of claim 27, wherein saidwaveguide and said blade are integrally formed as a unitary structurefrom a metal chosen from the group consisting of titanium, titaniumalloy, aluminum, aluminum alloy, and stainless steel 33-37. (canceled)38. The ultrasonic surgical device of claim 27, further comprising aclamp member having a curved tissue-engaging surface, said clamp memberpivotally supported adjacent the blade, wherein said tissue-engagingsurface has a curvature corresponding to the curvature of at least aportion of said first face of the blade, and further wherein the claimmember is selectively pivotable between an open position whereat theclamp member is spaced away from the blade and a closed position whereatthe clamp member can urge tissue against said first face of the blade.39-40. (canceled)
 41. A method of fabricating the ultrasonic surgicaldevice of claim 1 from a segment of round stock without Z-axis milling,comprising the steps of: (a) turning a segment of round stock to form anoutwardly curved surface of revolution adjacent a distal end of saidsegment of round stock; and (b) milling said round stock using an endmill in order to produce said first and second opposed faces; whereinsaid first and second opposed faces extend from the distal end of saidsegment of round stock through and proximally beyond said outwardlycurved surface of revolution, and said interior surfaces of said hookportions comprise the remaining portions of said surface of revolution.